Motion converter for electrically driven rotary oscillators



March 3, 1964 K. TRICK ETAL 3,122,879

MOTION CONVERTER FOR ELECTRICALLY' DRIVEN ROTARY OSCILLATORS Filed Sept.29, 1960 INVENTOM K. TPL'cA 7T6cLuZ BY Her/- 4 R. WoZZer A itzya.

United States Patent 3,122,879 MOTION CONVERTER FOR ELECTRICALLY DRIVENROTARY OSCILLATORS Kuno Trick, Tosstr. 41; Theodor Schulte,Tiersteinstr. 82;

and Fritz Herr, Kolpingstr. 18, all of Schramberg,

Germany; and Robert Wolber, Lauterbach, Holzle,

Germany Filed Sept. 29, 1960, Ser. No. 59,303 Claims priority,application Germany Oct. 1, 1959 5 Claims. (CI. 58-28) The inventionrelates to a driving mechanism for electrically-driven rotaryoscillators, particularly for wrist watches, with a swing fork actuatinga stepping wheel and whose swinging movement is limited by stops.

Such driving mechanisms are known for wrist watches in which at eachoscillation the stepping wheel of the hand movement is moved on onetooth by a pin fixed on the movement regulator or an ellipse. In thecase of such driving mechanisms it may happen that the movementregulator, due to a jolt, for example a sudden movement of the arm, isenergized to carry out such strong oscillations that the stepping wheelis moved on several teeth at each oscillation. Moreover the handmovement is not constantly in engagement with the movement regulator.This, however, engages the stepping Wheel for a relatively short timeduring an oscillation. To secure the stepping wheel against turning inthe intervals between the steps, a mechanically or magnetically actuatedlocking mechanism is generally provided which prevents at least backmovement of the stepping wheel. The forces exerted by this lockingmechanism on the stepping wheel can naturally only be so slight that, onthe occurrence of relatively great forces for example when setting thehands, these locking forces of the ordinary mechanism are overcome andthe stepping Wheel is advanced. The second hand is in this case moved inclockwise direction or in counter-clockwise direction with great jumpsand exact setting of the hands is not possible.

The object of the invention is to produce a driving mechanism forelectrically driven rotary oscillators, in which the fork is held in itsextreme positions and in which the jumping or slipping of the steppingwheel is reliably prevented.

According to the invention, the fork is in operative connection with aholding member elastically acting on it and at least one of thecooperating parts is so shaped that for obtaining counter-directedforces in the two extreme positions of the fork, different parts of themembers come into operative connection with each other. In a mechanismwith a fork feeding the stepping wheel at each full oscillation, asafety cam is preferably provided in addition to the stepping oroperating cam in such a manner that it is located in a tooth gap of thestepping wheel when the fork is in its extreme or end position and thestepping or operating cam has left a tooth gap of the stepping wheel.

An embodiment of the invention is hereinafter described by way ofexample with reference to the accompanying drawing, in which the singlefigure is a diagrammatic side view showing an arrangement in which theoperating fork carries an operating cam and a safety cam.

The rotary oscillator is designated by 80 and carries a pin 82 engagingthe limiting fork 81. The swinging movement: of the fork or pallet 81 islimited by stops {83 and 84. Pins 86 and 87 are mounted on the arm ofthe fork 81 but do not both have to function to move on the steppingwheel at each half oscillation of the movement regulator 80, themovement of the stepping wheel being effected only by the pin 87 whereasthe pin 86 only serves as run-through safety stop for the stepping wheel88. The limiting fork has an aperture 89 by which the arm 85 thereof isdivided into two parallel strips and 91 which cooperate with a permanentmagnet 92. Thus the fork 81 made from magnetic material is held in itsend positions by the stops 83 and 84.

The magnetic holding forces are however only strong enough that they canbe overcome by the switching impulses of the rotary oscillator.

The drawing shows the fork or pallet 81 in its initial end position inwhich it bears against the stop 83 and is held thereto by the permanentmagnet 92 acting on the strip 9t). In this end position the locking pin86 is located in a tooth gap of the stepping wheel 88, whereas theoperating pin 87 is outside the periphery of the stepping wheel. ()n thefork 31 being moved inwards the operating pin 87 is moved in thedirection towards the stepping wheel and comes into contact with one ofthe teeth thereof with the result that the stepping wheel is turned sofar that the magnetic forces become so strong in relation to the nextfollowing tooth that the stepping wheel moves on one tooth. During thismovement of the stepping wheel, the safety pin 86 is not located in oneof the tooth gaps so that the step movement is not impeded. On the otherhand the operating pin 87 now stands in a tooth gap of the steppingWheel (see broken line contours). One of the pins 86, S7 is alwayslocated in a tooth gap so that slipping or mounting the stepping wheel88 in the event of any increased moments of rotation occurring, isprevented in any case.

However, under normal operating conditions the stepping wheel is held bythe magnet 93 in the intervals between the stepping-on movements, sothat the safety pin 86 does not as a rule come into contact with the steping wheel 83 at all.

It has been found that particularly good operation of the arrangementaccording to the invention is obtained if the flat wall face of theoperating pin 87 is substantially tangential to its direction ofmovement, whereas the flat face of the safety pin 86 is approximatelyperpendicular thereto.

We claim:

1. Driving mechanism for an electrically driven rotary oscillatorespecially for wrist watches, comprising a stepping wheel rotatablymounted and having a plurality of teeth with tooth gaps between theteeth in the periphery of the wheel, a swing fork pivoted to oscillatebetween stop elements and pivoted intermediate its ends, an elasticholding means to hold the fork in its end positions against the stopelements, and a pair of spaced pins mounted on one end of the swing forkto cooperate with the teeth in the stepping wheel, one of the pins beingan operating pin and the other a safety pin so that when the operatingpin has moved the stepping wheel and is retracted out of contact withthe teeth of the wheel the safety pin will be situated in a tooth gapfree of contact with the stepping wlheel when said fork is in one ofsaid end positions.

2. Controlling mechanism according to claim 1, in

which the pins each have a curved portion which is elliptic in contourand a flat portion.

3. Controlling mechanism according to claim 1, in which each pin has afiat surface with such fiat surface of the operating pin beingsubstantially tangential to the direction of movement of the pin and thefiat surface of the safety pin is substantially vertical as to themovement.

4. Controlling mechanism according to claim 1, in which at least onepermanent magnet is provided secured in position in operative relationwith the stepping wheel, and in which the teeth of the stepping wheelare composed of magnetizable material whereby the teeth of the wheelwill form armatures for the magnet to retain the wheel in a position ofrest when the operating pin is retracted out of contact with the teethof the wheel.

5. Controlling mechanism according to claim 1, in

'4 which said holding means comprises a pair of spaced strips ofmagnetizaole material on said fork and a permanent magnet is securelymounted at right angles to the movement of the fork so that the stripswill be influenced by the magnet in each end position of the oscillatingfork.

References Cited in the file of this patent UNITED STATES PATENTS 102,865,163 Ensign et al Dec. 23, 1958 2,971,324 Beyner Feb. 14, 1961FOREIGN PATENTS 647,217 France July 24, 1928 15 923,788 France Feb. 24,1947

1. DRIVING MECHANISM FOR AN ELECTRICALLY DRIVEN ROTARY OSCILLATORESPECIALLY FOR WRIST WATCHES, COMPRISING A STEPPING WHEEL ROTATABLYMOUNTED AND HAVING A PLURALITY OF TEETH WITH TOOTH GAPS BETWEEN THETEETH IN THE PERIPHERY OF THE WHEEL, A SWING FORK PIVOTED TO OSCILLATEBETWEEN STOP ELEMENTS AND PIVOTED INTERMEDIATE ITS ENDS, AND ELASTICHOLDING MEANS TO HOLD THE FORK IN ITS END POSITIONS AGAINST THE STOPELEMENTS, AND A PAIR OF SPACED PINS MOUNTED ON ONE END OF THE SWING FORKTO COOPERATE WITH THE TEETH IN THE STEPPING WHEEL, ONE OF THE PINS BEINGAN OPERATING PIN AND THE OTHER A SAFETY PIN SO THAT WHEN THE OPERATINGPIN HAS MOVED THE STEPPING WHEEL AND IS RETRACTED OUT OF CONTACT WITHTHE TEETH OF THE WHEEL THE SAFETY PIN WILL BE SITUATED IN A TOOTH GAPFREE OF CONTACT WITH THE STEPPING WHEEL WHEN SAID FORK IS IN ONE OF SAIDEND POSITIONS.